Prebiotic Treatment in People With Schizophrenia

Inclusion Criteria: 1. DSM-5 diagnosis of schizophrenia or schizoaffective disorder; 2. Age 18-60 years; 3. Considered clinically stable by the treating psychiatrist; 4. Currently treated with an antipsychotic, with no dose changes in last 14 days; 5. Ability to participate in the informed consent process, as determined by a score of 10 or greater on the Evaluation to Sign Consent; 6. BMI ≤ 40 Exclusion Criteria: 1. Gastrointestinal disorders, including, but not limited to Crohn's Disease, Irritable Bowel Syndrome, Celiac Disease, whose pathology or treatment could alter the presentation or treatment of schizophrenia or significantly increase the risk associated with the proposed treatment protocol 2. Organic brain disorder, including cerebrovascular accident; epilepsy; traumatic brain injury, Loss of consciousness (LOC) for more than 30 minutes 3. Intellectual disability 4. Acute antibiotic use 5. Immune therapy within the last three months 6. Prebiotic or probiotic treatment within the last three months 7. Inability to understand English 8. Inability to cooperate with study procedures 9. Pregnant or lactation secondary to pregnancy 10. Participants who meet DSM 5 criteria for alcohol or substance misuse (except caffeine and nicotine) within the last 3 months will be excluded. Participants who meet DSM 5 criteria for marijuana misuse - mild will be included in the study.